Prevalence, Virulence, and Antibiotics Gene Profiles in Lactococcus garvieae Isolated from Cows with Clinical Mastitis in China

Abstract

Lactococcus garvieae (L. garvieae) is a pathogenic gram-positive, catalase-negative (GPCN) bacterium that causes bovine mastitis. A total of 49 L. garvieae isolates were identified from 1441 clinical mastitis (CM) samples. The pathogenic effects of L. garvieae were studied with two infection models: bovine mammary epithelial cells cultured in vitro and murine mammary infections in vivo. The overall farm prevalence was 15.5% (13/84 farms in 9/19 provinces) and sample prevalence was 3.40% (49/1441). Post-treatment somatic cell count (SCC) post L. garvieae infection was significantly higher than the other GPCN pathogens isolated, and the bacteriological cure fraction was 41.94% (13/31) after intramammary antibiotic treatment. All L. garvieae isolates were resistant to rifaximin, 12.24% of isolates were resistant to cephalexin, and 10.20% (5/49) were multidrug-resistant (MDR). The most prevalent virulence genes were Hemolysin 1 (hly1)(100%), Hemolysin 2 (hly2) (97.96%), NADH oxidase (NADHO) (100%), Superoxide dismutase (SOD) (100%), Adhesin Pav (Pav) (100%), Adhesin PsaA (PsaA) (100%), Enolase (eno) (100%), Adhesin cluster 1(AC1) (100%), Adhesin cluster 2 (AC2) (100%), and several exopolysaccharides. L. garvieae rapidly adhered to bovine mammary epithelial cells, resulting in an elevated lactate dehydrogenase release. Edema and congestion were observed in challenged murine mammary glands and bacteria were consistently isolated at 12, 24, 48, 72, and 120 h after infection. We concluded that L. garvieae had good adaptive ability in the bovine and murine mammary cells and tissue. Given the resistance profile, penicillin and ampicillin are potential treatments for CM cases caused by L. garvieae.

Lactococcus garvieae exerts a critical role in inducing inflammation in dairy mastitis by triggering NLRP3 inflammasome-mediated pyroptosis in MAC-T cells

“…The NLRP3 inflammasome plays a crucial role in the host's defense against bacterial infections [62], and is indispensable for L. garvieae in inducing inflammation and pyroptosis in MAC-T cells. Previous studies indicated the involvement of L. garvieae in mastitis development in cows [39]. However, there remains a lack of understanding regarding the molecular mechanisms by which L. garvieae induces mastitis.…”

“…The two bacterial strains of L. garvieae LG41 and LG47 were stored at a temperature of -20°C in our laboratory before they were used for the study. The bacterial collection procedure was previously published, and more details on it can be found there [39]. The preserved bacterial strains were propagated in Sheep blood agar and brain heart infusion (BHI) (Qingdao Haibo Biotechnology Co., Ltd.).…”

First identification, molecular characterization, and pathogenicity assessment ofLactococcus garvieaeisolated from cultured pompano in Taiwan

“…The capsules present in L. garvieae are not only considered important virulence factors but are also collectively considered a defining characteristic of their serotype and phenotype classification (Salighehzadeh et al, 2020). The capsule may also play a protective role against host immune responses, antimicrobial agents, and environmental stressors (Voelz & May, 2010) in L. garvieae (Xie et al, 2023). Previously, it was believed that pathogenic L. garvieae isolates possessed capsules (KG−/agglutinating), whereas non‐capsulated isolates (KG+/non‐agglutinating) were non‐pathogenic (Barnes & Ellis, 2004; Ooyama et al, 2006).…”

“…garvieae (Xie et al, 2023). Previously, it was believed that pathogenic L. garvieae isolates possessed capsules (KG−/agglutinating), whereas non-capsulated isolates (KG+/non-agglutinating) were non-pathogenic (Barnes & Ellis, 2004;Ooyama et al, 2006).…”

“…Lactococcosis is an acute hemorrhagic septicemia in fish caused by Lactococcus garvieae that occurs at varying temperatures and salinities (Austin & Austin, 2007; Neagoe et al, 2016). The host range of L. garvieae is immensely diverse, as its infection has not only been recorded in different fish and shellfish species (Shahin et al, 2022), but also in various higher vertebrates, such as pigs (Tejedor et al, 2011), buffalo (Xie et al, 2023), dogs and cats (Eldar et al, 1996), and poultry meat (Barakat et al, 2000). In addition, the zoonotic potential of lactococcosis has been observed on several occasions, making the aquaculture industry vulnerable (Gibello et al, 2016; Soltani et al, 2021; Wang et al, 2007).…”